Anton Zeilinger (; born 20 May 1945) is an Austrian quantum physicist and Nobel laureate in physics of 2022. Zeilinger is professor of physics emeritus at the University of Vienna and senior scientist at the Institute for Quantum Optics and Quantum Information of the Austrian Academy of Sciences. Most of his research concerns the fundamental aspects and applications of quantum entanglement.
In 2007, Zeilinger received the first Inaugural Isaac Newton Medal of the Institute of Physics, London, for "his pioneering conceptual and experimental contributions to the foundations of quantum physics, which have become the cornerstone for the rapidly-evolving field of quantum information". In October 2022, he received the Nobel Prize in Physics, jointly with Alain Aspect and John Clauser for their work involving experiments with entangled photons, establishing the violation of Bell inequalities and pioneering quantum information science.
Early life and education Anton Zeilinger was born in 1945 in Ried im Innkreis, Upper Austria, Austria. He studied physics at the University of Vienna from 1963 to 1971. He received a doctorate from the University of Vienna in 1971, with a thesis on "Neutron depolarization measurements on a Dy-single crystal" under Helmut Rauch. He qualified as a university lecturer (habilitation) at the Vienna University of Technology in 1979.For a history of Zeilinger's career in the Austrian context of the rise of quantum foundations and quantum information, see
Career
In the 1970s, Zeilinger worked at the Vienna Atominstitut as a research assistant and later as an associate researcher at the Massachusetts Institute of Technology Neutron Diffraction Laboratory until 1979, when he accepted the position of assistant professor at the same Atominstitut. That year he qualified as a university professor at the Vienna University of Technology.
In 1981 Zeilinger returned to MIT, as an associate professor on the physics faculty, until 1983. Between 1980 and 1990 he worked as a professor at the Vienna University of Technology, the Technical University of Munich, the University of Innsbruck and the University of Vienna.
He was also the scientific director of the Institute for Quantum Optics and Quantum Information in Vienna between 2004 and 2013. Zeilinger became professor emeritus at the University of Vienna in 2013. He was president of the Austrian Academy of Sciences from 2013 till 2022.
Since 2006, Zeilinger is the vice chairman of the board of trustees of the Institute of Science and Technology Austria, an ambitious project initiated by Zeilinger's proposal. In 2009, he founded the International Academy Traunkirchen, which is dedicated to the support of gifted students in science and technology. He is a fan of the Hitchhiker's Guide To The Galaxy by Douglas Adams, going so far as to name his sailboat 42.
Research
Quantum teleportation Zeilinger published one of the first realizations of quantum teleportation of an independent qubit.D. Bouwmeester, J. W. Pan, K. Mattle, M. Eibl, H. Weinfurter & A. Zeilinger, Experimental Quantum Teleportation, Nature 390, 575–579 (1997). Abstract . Selected for the Nature "Looking Back" category of classic papers from Nature's archive; one of ISI's "Highly Cited Papers".Popescu's group published similar results around the same time. He later expanded this work to developing a source for freely propagating teleported qubitsJ.-W. Pan, S. Gasparoni, M. Aspelmeyer, T. Jennewein & A. Zeilinger, Experimental Realization of Freely Propagating Teleported Qubits, Nature 421, 721–725 (2003). Abstract .Selected by the International Institute of Physics as one of the top ten Physics Highlights in 2003. and quantum teleportation over 144 kilometers between two Canary Islands.X.-S. Ma, T. Herbst, T. Scheidl, D. Wang, S. Kropatschek, W. Naylor, B. Wittmann, A. Mech, J. Kofler, E. Anisimova, V. Makarov, T. Jennewein, R. Ursin & A. Zeilinger, Quantum teleportation over 143 kilometres using active feed-forward, Nature 489, 269–273 (2012). Abstract . Ranked as a "highly cited paper" by Thomson Reuters' Web of Science, placing it in the 1% of the academic field of physics based on a highly cited threshold for the field and publication year. Quantum teleportation is an essential concept in many quantum information protocols. Besides its role for the transfer of quantum information, it is also considered as an important possible mechanism for building gates within quantum computers.
Entanglement swapping – teleportation of entanglement Entanglement swapping is the teleportation of an entangled state. After its proposal,M. Zukowski, A. Zeilinger, M. A. Horne & A.K. Ekert, Event-Ready-Detectors Bell Experiment via Entanglement Swapping, Phys. Rev. Lett. 71, 4287–90 (1993). . entanglement swapping was first realized experimentally by Zeilinger's group in 1998.J.-W. Pan, D. Bouwmeester, H. Weinfurter & A. Zeilinger, Experimental entanglement swapping: Entangling photons that never interacted, Phys. Rev. Lett. 80 (18), 3891–3894 (1998). . It was then applied to carry out a delayed-choice entanglement swapping test.X.-S. Ma, S.Zotter, J. Kofler, R. Ursin, T. Jennewein, Č. Brukner & A. Zeilinger, Experimental delayed-choice entanglement swapping, Nature Physics 8, 479–484 (2012). Abstract .
Entanglement beyond two qubits – GHZ-states and their realizations
Anton Zeilinger contributed to the opening up of the field of multi-particle entanglement. In 1990, he was the first with Daniel Greenberger and Michael Horne to work on entanglement of more than two qubits. This paper has become a citation classic. The resulting GHZ theorem (see Greenberger–Horne–Zeilinger state) is fundamental for quantum physics, as it provides the most succinct contradiction between local realism and the predictions of quantum mechanics.
GHZ states were the first instances of multi-particle entanglement ever investigated. Ranked as a "highly cited paper" by Thomson Reuters' Web of Science, placing it in the 1% of the academic field of physics based on a highly cited threshold for the field and publication year.
Finally, in 1999, he succeeded in providing the first experimental evidence of entanglement beyond two particlesD. Bouwmeester, J.-W. Pan, M. Daniell, H. Weinfurter & A. Zeilinger, Observation of three-photon Greenberger–Horne–Zeilinger entanglement, Phys. Rev. Lett. 82 (7), 1345–1349 (1999). Abstract . and also the first test of quantum nonlocality for GHZ states.J.-W. Pan, D. Bouwmeester, M. Daniell, H. Weinfurter & A. Zeilinger, Experimental test of quantum nonlocality in three-photon Greenberger-Horne-Zeilinger entanglement, Nature 403, 515–519 (2000). Abstract .
Quantum communication, quantum cryptography, quantum computation
In 1998 (published in 2000), his group was the first to implement quantum cryptography with entangled photons. This paper was featured in several popular science magazines, both online and in print. He then applied quantum entanglement to optical quantum computation, where in 2005,P. Walther, K.J. Resch, T. Rudolph, E. Schenck, H. Weinfurter, V. Vedral, M. Aspelmeyer & A. Zeilinger, "Experimental one-way quantum computing", Nature 434 (7030), 169–176 (2005). Abstract he performed the first implementation of one-way quantum computation. This is a protocol based on quantum measurement as proposed by Knill, Laflamme and Milburn.E. Knill, R. Laflamme & G. J. Milburn, (2001) "A scheme for efficient quantum computation with linear optics", Nature 409, 46–52 Abstract
The experiments of Zeilinger and his group on the distribution of entanglement over large distances began with both free-space and fiber-based quantum communication and teleportation between laboratories located on the different sides of the river Danube. This was then extended to larger distances across the city of Vienna and over 144 km between two Canary Islands, resulting in a successful demonstration that quantum communication with satellites is feasible. His dream is to put sources of entangled light onto a satellite in orbit. A first step was achieved during an experiment at the Italian .P. Villoresi, T. Jennewein, F. Tamburini, M. Aspelmeyer, C. Bonato, R. Ursin, C. Pernechele, V. Luceri, G. Bianco, A. Zeilinger & C. Barbieri,Experimental verification of the feasibility of a quantum channel between Space and Earth , New Journal of Physics 10, 033038 (2008). Highlight of New J. Phys. for 2008.
Further novel entangled states With his group, Anton Zeilinger made many contributions to the realization of novel entangled states. The source for polarization-entangled photon pairs developed with Paul Kwiat when he was a PostDoc in Zeilinger's groupP.G. Kwiat, K. Mattle, H. Weinfurter, A. Zeilinger, A.V. Sergienko & Y.H. Shih, New High-Intensity Source of Polarization-Entangled Photon Pairs, Phys. Rev. Lett. 75 (24), 4337–41 (1995). . is used in many laboratories. The first demonstration of entanglement of orbital angular momentum of photons opened up a new field of research in many laboratories.A. Mair, A. Vaziri, G. Weihs & A. Zeilinger, Entanglement of the orbital angular momentum states of photons, Nature 412 (6844), 313–316 (2001). Abstract .
Macroscopic quantum superposition Zeilinger is also interested to extend quantum mechanics into the macroscopic domain. In the early 1990s, he started experiments in the field of atom optics. He developed a number of ways to coherently manipulate atomic beams, many of which, like the coherent energy shift of an atomic De Broglie wave upon diffraction at a time-modulated light wave, have become part of today's ultracold atom experiments. In 1999, Zeilinger abandoned atom optics for experiments with very complex and massive macro-molecules – fullerenes. The successful demonstration of quantum interference for these C60 and C70 moleculesM. Arndt, O. Nairz, J. Voss-Andreae, C. Keller, G. van der Zouw & A. Zeilinger, Wave-particle duality of C60 molecules, Nature 401, 680–682 (1999). Abstract . Selected by the American Physical Society as a physics highlight of 1999. in 1999 opened up a very active field of research.
In 2005, Zeilinger with his group investigated the quantum physics of mechanical cantilevers. In the year 2006 along with Heidmann in Paris and Kippenberg in Garching they demonstrated experimentally the self-cooling of a micro-mirror by radiation pressure, that is, without feedback.S. Gigan, H. R. Böhm, M. Paternostro, F. Blaser, G. Langer, J. B. Hertzberg, K. Schwab, D. Bäuerle, M. Aspelmeyer & A. Zeilinger, Self-cooling of a micro-mirror by radiation pressure, Nature 444, 67–70 (2006). Abstract .
Using orbital angular momentum states, he was able to demonstrate entanglement of angular momentum up to 300 ħ.R. Fickler, R. Lapkiewicz, W. N. Plick, M. Krenn, C. Schäff, S. Ramelow & A. Zeilinger, Quantum entanglement of high angular momenta, Science 338, 640–643 (2012). Abstract . Selected as one of the top 10 breakthroughs of the year 2012 by IOP's Physics World. Also featured in DPG's Physik Journal. Ranked as a "highly cited paper" by Thomson Reuters' Web of Science, placing it in the 1% of the academic field of physics based on a highly cited threshold for the field and publication year.
Further fundamental tests